The present invention relates to an assembly for testing physical capabilities of a human test subject. More particularly, a machine and method are disclosed for measuring range of motion of to a body joint formed between two connected body portions.
A commonly measured physical capability is the range of motion of a particular body joint. The range of motion is the angular movement of one body portion to that of a second body portion from a reference position to a second position in a preselected path. Quantitative analysis of the range of motion is sometimes necessary in order to ascertain the extent of injury to the body joint. Other instances include the continued measurement of a person's capabilities during physical therapy.
Range of motion devices and systems to measure the range of motion of the body joint are commonly known. Generally, the device includes a first support structure connected to a first body portion of the body joint to be tested. A second support structure is connected to a second body portion forming the body joint. An angular measuring device connected between the first support structure and the second support structure measures the angular displacement of the second body portion relative to the first body portion. The angular measuring device determines the change in angular position between the first and second support structures, which corresponds to the angular change of position of the first body portion to the second body portion.
The range of motion of a body joint can be quantified as two separate motion components. The first motion component, commonly called "active" motion, is defined as the angular range the joint can be voluntarily articulated from the reference position in the preselected path. Whereas, the second component of motion, commonly called "passive" motion, is that remaining angular motion that an examiner can further cause by exerting some force on a body portion connected to the joint. Usually the amount of force that the examiner applies is determined by his or her experience and good judgment, or by complaints of pain from the patient. Although the passive motion tests are considered to be very important in defining the complete range of motion of the joint, the results obtained are questionable because the amount of force applied during the passive motion test is presently uncontrolled.